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Six reasons to be optimistic about Lake Ontario's future

Shimmering fish sparkle beneath the water&rsquo;s surface, tiny glimmers of
hope that Lake Ontario can be renewed and return to full health again.

By Leslie ScrivenerFeature Writer

Fri., July 8, 2011

Walleye, sharp-toothed, gold and olive in colour, appear to be back in Lake Ontario, after decades of very low number. Lilies grow in wetlands that were once sodden mud flats. Shimmering fish sparkle beneath the water’s surface, tiny glimmers of hope that Lake Ontario can be renewed and return to full health again.

They are signs that the fish, wildlife and birds that were extirpated — locally extinct — can return to make their home in and near the lake’s waters.

The losses have been extreme. Nearly 60 per cent of original wetlands have been destroyed on the Canadian side of Lake Ontario, even more between Toronto and the Niagara River. In some parts of southwestern Ontario, the loss has reached 90 per cent, one of the highest rates in the world.

Invasive species continue to threaten the biodiversity of the lake. They include the zebra mussel and the parasitic sea lamprey, which attaches itself to fish with its sucker mouth.

Still, there are pockets of improvement. “The sheer number of waterfowl that rest on the lake during migratory period are more than anyone would believe, well over a million,” says ecologist Tys Theysmeyer. “It does remind you it is a great lake.”

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“Think back to the days when Lake Ontario and Lake Erie were being written off and polluted and unhealthy,” biologist Marion Daniels says of the 1960s and 1970s. Those would be the days when algae bloomed, when dead smelt littered the shoreline, when foam bubbled grey and noxious.

“That’s been reversed in a lot of different ways.

“We have to take care of the little things. If we’re successful in taking care of the little things, little things become big improvements.”

In that spirit, the Star highlights some recent ecological success stories in and around Lake Ontario.

Marshland miracles

The common carp, a half million pounds of sucker-mouthed, whiskered, heavy-scaled bottom feeders, had overtaken Cootes Paradise, part of the Royal Botanical Gardens between Hamilton and Burlington. It looked like a mud flat. Carp, introduced in the late 19th century as a replacement for salmon, sucked up sediment, rototilled plant life and left the water, polluted by runoff from agricultural land use and urban sewage, a murky mess. In one of North America’s largest wetland rehabilitation projects, which included a fishway to keep out the carp, it has become a true marshland paradise with waving cattails, pelicans (during spring migration), mink, muskrat, perch, sunfish and pike. Fifty native plants once at risk have returned. Most delightful: yellow water lilies and wild rice.

Marshlands: Bogs, swamps and shallow water — like the South Pasture Swamp at the Royal Botanical Gardens — are threatened by agricultural, industrial and urban development. In the past, wetlands were considered breeding grounds for mosquitoes that should be drained or paved. But they are to be treasured. They brim with more life than any other ecosystem — 200 species of birds and 50 species of mammals are dependent on wetlands, which are often sanctuaries for endangered species.

Wetlands: Black-crowned night herons — these are at Cootes Paradise — are wetland-loving birds that rest communally by day and fish by night. They are one of the 300 species of birds found at the Royal Botanical Gardens.

Return of the native

The water is cold and fast-running, the gravel clean in Duffins Creek, which spills into Lake Ontario at Ajax, creating a perfect nursery for Atlantic salmon. It’s one of four waterways — including the Credit River, the Humber River and Cobourg Brook — rehabilitated in the past six years to welcome the once-flourishing native species, which vanished at the end of the 19th century. Dams, deforestation, agricultural runoff had made the streams inhospitable. Add to that overfishing — there were reports of thousands being caught in single night. Now, trees are being planted on the banks to increase shade and lower water temperature, and fences are being erected to prevent livestock from polluting the stream and damaging spawning beds. Strains of salmon from Nova Scotia, Quebec and Maine have been hatched and released in Duffins Creek, some 800,000 so far. Scientists are watching to see which is the hardiest and are hoping for signs of wild reproduction.

Atlantic salmon: Since 2006 some 2.5 million young Atlantic salmon have been released into creeks and rivers that empty into Lake Ontario, a collaborative effort by 50 environment-minded citizens, government and private companies. A native species — descended from saltwater fish that adapted to freshwater — Atlantic salmon were last seen in local streams in 1896.

Great big birds

The big-winged birds have returned. Trumpeter swans, the largest of North American waterfowl, had not been seen in Ontario since the 19th century. They had been hunted to near extinction. Hundreds now overwinter in Burlington Bay thanks to the work of volunteers led by retired Ministry of Natural Resources biologist Harry Lumsden, who started a swan restoration program in 1982. Now the indigenous species with the memorable honk is self-sustaining. Another impressive bird, the bald eagle, hadn’t been seen near Lake Ontario in more than 50 years. Last fall, five were spotted at Cootes Paradise in the Royal Botanical Gardens, and one pair has made a nest there, the first on Lake Ontario in decades. There were hopes that the couple might reproduce this year, but it’s likely the male is too young to breed. Once threatened by DDT — they’d eat fish contaminated by the now-banned pesticide — they have an abundance of catfish and sunfish and lots of forested real estate where they can thrive.

Trumpeter swan: the black-billed birds (different from the orange-billed mute swans) were wiped out in Ontario until restoration efforts in the 1980s. There are now about 700 Ontario trumpeters, a population that is growing but still considered fragile.

Bald eagle: Once close to extinction, the bird with the 2.4-metre wingspan has finally returned to Lake Ontario. Bald eagles need a generous amount of marsh space, 30 hectares or more, and a mature forest in which to nest.

Tiny, sparkly wonders

“It’s not super sexy,” says Gord MacPherson, “but the minnows are back.” Decades ago, the emerald shiner had fallen victim to a lake awash in detergent, fertilizer and sewage. The five-centimetre-long, iridescent fish had been displaced by alewife and smelt — you may have seen the latter washed up on the shore, says MacPherson, manager of habitat restoration for the Toronto and Region Conservation Authority. The shiners’ return signals a new balance in a clearer, cleaner lake. “On a nice summer day, when the lake is really calm, you can see bazillions of them. When I was a kid you couldn’t see them because of the algae.”

‘White bonfires’

Lake Ontario’s shifting, restless dunes, what the poet Al Purdy called “white bonfires in the sunlight,” are continually being restored. The world’s largest freshwater sand barrier is at Sandbanks Provincial Park, near Picton. The dunes are still recovering from 19th century disturbances, when local farmers sent their cows to graze on the dunes — the loss of vegetation led to widespread erosion. Entire trees could be lost beneath the blown sand. Rehabilitation efforts include planting trees — 50,000 in the past five years — and marram grass, a native species. Fencing and walkways help reduce trampling and the impact of wandering visitors.

Sand dunes: Lake Ontario sand dunes, which are being restored and protected, can include trees and unusual plant species.

Underwater explorers

How does development — a new pier or park — along Toronto’s shoreline affect the fish in the city’s harbour? In a program launched in June, 50 acoustic receivers placed in harbour waters will monitor the movement, temperature and depth of about 100 fish (northern pike, largemouth bass, walleye and common carp) fitted with transmitters. Each receiver will provide hundreds of thousands of records, including more precise data on spawning seasons. (That information can affect the timing of construction projects.) The $500,000 project, funded by three levels of government, is one of the most advanced fish-monitoring research projects in Canada.

Harbour research: Toronto and Region Conservation Authority staff were in Toronto Harbour in June aboard the Night Heron tagging fish with 2-centimetre-long acoustic monitors which will record their movements in the lake.

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